---
id: formats
title: Camera Formats
sidebar_label: Camera Formats
---

import useBaseUrl from '@docusaurus/useBaseUrl';

<div>
  <img align="right" width="283" src={useBaseUrl("img/example.png")} />
</div>

### What are camera formats?

Each camera device (see [Camera Devices](devices)) provides a number of capture formats that have different specifications. There are formats specifically designed for high-resolution photo capture, which have very high photo output quality but in return only support frame-rates of up to 30 FPS. On the other side, there might be formats that are designed for slow-motion video capture which have frame-rates up to 240 FPS.

### What if I don't want to choose a format?

If you don't want to specify the best format for your camera device, you don't have to. The Camera _automatically chooses the best matching format_ for the current camera device. This is why the Camera's `format` property is _optional_.

### What you need to know about cameras

To understand a bit more about camera formats, you first need to understand a few "general camera basics":

* Each camera device is built differently, e.g. _Telephoto devices_ often don't provide frame-rates as high as _Wide-Angle devices_.
* Formats are designed for specific use-cases, so formats with high resolution photo output don't support frame-rates as high as formats with lower resolution.
* Different formats provide different field-of-views (FOV), maximum zoom factors, color spaces (iOS only), resolutions, frame rate ranges, and systems to assist with capture (auto-focus systems, video stabilization systems, ...)

### Get started

Each application has different needs, so the format filtering is up to you.

To get all available formats, simply use the `CameraDevice`'s `.formats` property. See how to get a camera device in the [Camera Devices guide](devices).

:::note
You can also manually get all camera devices and decide which device to use based on the available `formats`.
:::

This example shows how you would pick the format with the _highest frame rate_:

```tsx
function App() {
  const devices = useCameraDevices('wide-angle-camera')
  const device = devices.back

  const format = useMemo(() => {
    return device?.formats.reduce((prev, curr) => {
      if (prev == null) return curr
      if (curr.maxFps > prev.maxFps) return curr
      else return prev
    }, undefined)
  }, [device?.formats])

  if (device == null) return <LoadingView />
  return (
    <Camera
      style={StyleSheet.absoluteFill}
      device={device}
      format={format}
    />
  )
}
```

Note that you don't want to simply pick the highest frame rate, as those formats often have incredibly low resolutions. You want to find a balance between high frame rate and high resolution, so instead you might want to use the `.sort` function.

### Sort

To sort your formats, create a custom comparator function which will be used as the `.sort` function's argument. The custom comparator then compares formats, preferring ones with higher frame rate AND higher resolution.

Implement this however you want, I personally use a "point-based system":

```ts
export const sortFormatsByResolution = (left: CameraDeviceFormat, right: CameraDeviceFormat): number => {
  // in this case, points aren't "normalized" (e.g. higher resolution = 1 point, lower resolution = -1 points)
  let leftPoints = left.photoHeight * left.photoWidth
  let rightPoints = right.photoHeight * right.photoWidth

  // we also care about video dimensions, not only photo.
  leftPoints += left.videoWidth * left.videoHeight
  rightPoints += right.videoWidth * right.videoHeight

  // you can also add points for FPS, etc

  return rightPoints - leftPoints
}

// and then call it:
const formats = useMemo(() => device?.formats.sort(sortFormatsByResolution), [device?.formats])
```

:::caution
Be careful that you don't `filter` out a lot of formats since you might end up having no format to use at all. (_Remember; not all devices support e.g. 240 FPS._) Always carefully sort instead of filter, and pick the best available format - that way you are guaranteed to have a format available, even if your desired specifications aren't fully met.
:::

### Props

The `Camera` View provides a few props that depend on the specified `format`. For example, you can only set the `fps` prop to a value that is supported by the current `format`. So if you have a format that supports 240 FPS, you can set the `fps` to `240`:

```tsx
function App() {
  // ...
  return (
    <Camera
      style={StyleSheet.absoluteFill}
      device={device}
      format={format}
      fps={240}
    />
  )
}
```

:::note
You should always verify that the format supports the desired FPS, and fall back to `undefined` (or a value that is supported, like `30`) if it doesn't.
:::

Other props that depend on the `format`:

* `fps`: Specifies the frame rate to use
* `hdr`: Enables HDR photo or video capture and preview
* `lowLightBoost`: Enables a night-mode/low-light-boost for photo or video capture and preview
* `videoStabilizationMode`: Specifies the video stabilization mode to use for this camera device


<br />

#### 🚀 Next section: [Taking Photos/Recording Videos](./capturing)
